The present invention generally relates to fuel systems in internal combustion engines and, more particularly, to a force motor including an electromagnetic rotary actuator having constant output torque characteristics and a governor cup, both permitting the correct positioning of the fuel rod in the fuel system of an internal combustion engine.
Electromagnetic actuators and other types of positioners are well known in the art. For example, in U.S. Pat. No. 3,735,302, an armature moves on a guide loft against the force of a return spring and in U.S. Pat. No. 3,883,839, an armature or actuator moves on a hollowed shaft containing bearings and a return spring. In U.S. Pat. No. 4,855,702, a shaft extends through a central opening in a frusto-conical projection and carries an armature having a reciprocally configured frusto-conical surface. Excitation of a winding which surrounds the frusto-conical projection moves the shaft linearly on bearings contained in the housing against the force of a return spring.
These types of electromagnetic actuators are suitable for typical positioning applications and can be used in internal combustion engines. However, it is desirable to provide an electromagnetic rotary actuator comprised of inexpensive materials which can be manufactured with low labor costs to permit the fuel rod of an internal combustion engine to be correctly positioned as required. It is also desirable to blindly connect the fuel rod to the rotary actuator without the use of fasteners to extend the useful life of the fuel control system and to allow an engine to be easily maintained.